Signors



April 9, 2 c. D. TUSKA ET AL 1,708,527

CONDENSER Filed Sept. 19, 1925 ATTORNEYS Patented Apr. 9, 1929.

UNITED STATES mam earner @FFEQEEZ.

CLARENCE 1). TUSKA AND PEEGIVAL H. SPENCER, 0F HARTFORD, CONNECTICUT, A-

SIGNORS, BY MESNE ASSIGNMENTS, TO RADIO CORPOEA TIQIT G]? AMERICA, A CO1:

PORATION OF DELAWARE.

CGNDEIISER.

Application filed September The present invention relates to a combined condenser and grid leak for use in the circuits of electron tubes such as are employed in radio receiving apparatus.

Condensers of this character may be employed in the grid circuit of the electron tube to raise the potential of the grid member or they may be used as a bypass in the plate circuit. The object of the invention is to provide a condenser unit in which a condenser. suitable for use in the grid or plate circuit of an electron tube, is molded within a block of insulating material which serves to maintain the component parts of the condenser in permanently assembled relation and protect the same from dust, moisture, and injury.

The invention consists in the improved condenser and grid leak hereinafter de scribed and claimed, the advantages of which will be apparent to those skilled in the art.

In the drawings, 7

Fig. 1 is a top plan view of a condenser unit constructed in accordance with the present invention;

Fig. 2 is a side elevational View of the same;

Fig. 3 is a cross sectional view through the condenser unit taken on the line 33 of Fig. 4';

Fig. 4 is a sectional View taken on the line 4.t of Fig. 3; and

Fig. 5 is a view similar to Fig. 4: that shows an alternative form oi the invention.

Referring to the drawings in detail, the combined condenser and grid leak unit comprises acondenser 1 and grid leak (5 embedded in a block of hardened plastic insulating material 2 molded into the form shown.

The condenser comprises a supporting core member 3 consisting of. a suitable dielectric such as a flat strip of cardboard, mica, or the like, and conductors 4 and 5 consisting of; conductor material such as strips of metal at opposite sides of the said member 3. The conductors 4 and 5 are each secured to the member 3 at the ends thereof with their free unfastened ends in overlapped relation upon its respective side of the core. 7 v

A resistance element 6 may be desired in connection with the condenser and preferably consists of a resilient strip of dielectric 18, 1923. Serial No. 663,601.

material coated upon its upper side with carbon or any other conductive material capable of producing the desired value of resistance. The uncoated under side of the said element 6 is preferably incontact with the conductor i as shown. It may be desirable to employ a. resistance element in another form, such as a resistance wire or the like which may well be accomplished without departing from the scope of the invention.

A screw threaded binding post 7 is provided to secure together the conductor 4-, dielectric core member 8 and resistance element 6 while a similar screw 8 secures the other conductor 5 to the other end of the member 3 and element 6. Collars 9 in threaded engagement with the binding posts 7 and 8 are provided and by the means of which the parts are securely and firmly clamped together to form a condenser assembly preparatory to being embedded in the molded insulating material.'

it will be noted that the conductors i and 5 are spaced apart by the dielectric member 3 which may be of any desired material suitable for holding the members separated against a mechanical connection. Also as a novel feature the resistance element connects the binding posts and tends to hold them in spaced apart relation so the comparatively thin elements form an assembled flat thin unit capable of withstanding the pres sure, employed in the molding operation, without destruction or injury which would tend to alter or destroy the characteristics of the unit.

As an alternative form, it may be desir able to provide a second resistance element 11 as best shown in Fig. 5 and which it will be observed is located underneath the conductor This element 11 is preferably similar to the element. 6 and has its uncoated side adjacent the conductor 5.

These resistance elements 6 and 11 function to stiilen and support the condenser unit and tend to prevent the end edges oi the overlapping conductors from breaking through the dielectric core'3 or the molding material squeezing in between said conductors and dielectric during the compressing and molding operation.

The flat conductors 4L- and 5 are preferably narrower than the dielectric member 3 so as to leave a margin of the member 3 at each 1 side of the members 4 and 5. The conductors are arranged to overlap one another in position as completely as possible without being short circuit'ed by contact with the collars 9, and when so positioned, reinforce one another against the distortion during the molding operation.

After being constructed as above de scribed, the condenser is embedded in suitable moldable insulating material such as rubber, phenol condensation product, rednianol or the like, the latter completely surrounding the condenser and molded thereto within a mold adapte'dto shape the material .into the term of the block shown. The posts 7 and 8 and collars 9 project be- ,yond one of the side faces of the block 2 for connection with circuit wires.

Thumb nuts not shown, may be screwed on the ends of the binding posts to clamp a Wire or the like to the projecting face of the collars 9.

The ends of the block 2 are rounded or curved as shown about axis coincident with the axes of the posts 7 and 8 thus providing a block of neat and pleasing appearance and one having no sharp corners to become mutilated. I

Between each binding post and end eof the block 2 an opening 10 is provided that extends from one side to the other in a direction parallel to the axes of the binding posts. These openings 10 may be employed. to receive screws, belts or the like for, securing the block to a support or may he used for the passage of the circuit Wires as they leave thelbinding posts.

By incasing the condenser elements in the block of insulating material as Irene-in described, s-ai'd elements are positively and qermanently maintained in proper -assemled relation and they are of course adecpiately protected fron'rinjury. The conc enser unit is of a form convenient to element, a second contact memher joining the other of said plates and the other end of the resistance membelj and a unitary mold insulating casing formed around and contacting with the outer "surface of the assembly formed by said parts except a portion'of saidcontact members, H r

In testimony whereof we have afiixed our signatures. v V

CLARENCE TUS KA. I PERCIVAL H SPYENCER. 

